Database systems may scale read-oriented workloads by the addition of computing nodes that maintain replicas of some or all of a collection of data. Typically, each computing node may maintain a copy of the data and a set of corresponding indexes. Read-oriented workload may be distributed among the computing nodes by a load balancing mechanism that distributes query execution tasks among the computing nodes. Accordingly, each of the computing nodes may process queries using by retrieving an appropriate set of data from its replica of the collection of data. The execution of certain queries on a computing node may be improved by using one or more of the set of indexes.